David Taylor was in a happy, long-term relationship when it first emerged that he had a secret daughter called Jez who was living only a few miles away.

The Glastonbury politician, who could be elected as the Green Party's first MEP this week, was wearing a long silver wig with a helium balloon stamped with "I am 40" taped to his back the day he first heard about her. It was his birthday party and among the crowd of 300 was an attractive woman with whom he had shared a summer romance 14 years before.

Chrissy Peters had believed that the father of her 12-year-old daughter was a musician whom both she and Taylor knew. The musician, who had a big following in Glastonbury, was at David Taylor's party that night and she had come along to hear him play. It was when she saw her two former boyfriends standing barely three feet away from one another that she realised that she had made a terrible mistake. "It suddenly struck me that David was really Jez's dad," she recalls. "The resemblance with my daughter was startling."

It was with a sense of deep foreboding that she set out to tell the politician the truth. "It took me four months to decide whether to give the letter to him," says Chrissy, who works at a charitable trust in Glastonbury. "I agonised. But I knew how important finding out your roots and real parentage are to people. I didn't know what his reaction would be."

Ironically, she chose a public meeting on genetics where Taylor was the keynote speaker to tell him the news. After he had finished his speech, she handed him an envelope marked "private" and told him not to open it until he had left the building.

The letter began, "I think you may be the father of my daughter." Taylor pulled up in a lay-by on the way home to read the letter that changed his life. "It is one of those sentences that most men dread," he says. "But I had this feeling of complete and utter joy. I knew that the news was true immediately."

DNA tests confirmed the connection but it took some weeks before a proper meeting with his daughter was set up - she didn't want to see him until the results were known. However, they almost met by accident before then. At the doctor's, where their blood was tested for a genetic match, the three found themselves in the same waiting room and Taylor had to dive into the nurse's room so that his daughter - who can look uncannily familiar - didn't catch a glimpse of him.

"I found out later she did see me, in fact," he says. "I was very nervous."

The lay-by where Taylor first learned he was a dad has become a place of deep significance in his life. He says he still gets a thrill when he drives past. The other week he took Jez, who is now 13, to see the place where he had first learned of her existence. She was not quite as struck by its significance as he was, however. "In his eyes it's very important," she says diplomatically.

While for some men, the revelation that you have a teenage daughter could come as an unwanted surprise, for David, who has been unable to have children with his partner Bettina, it has become the focus of his life.

"Most men dread the fact that their past might catch up with them, but in my case it was this joyful experience," he says. "The moment I learned about her was so happy. I had always wanted to have a child but had been unable to. Suddenly one pops up just down the road."

Taylor is keen to introduce his daughter to her roots. They've even visited the local church where her ancestors have been buried for hundreds of years and the vaults of the family solicitor's firm. She's travelled round England to meet cousins, aunts and uncles who have a clutch of titles and houses. On one occasion Jez, who lives on a housing association estate, found herself in Clifton Castle, in Yorkshire. "It was the biggest house I have ever been to," says Jez. "I don't go to many castles."

Jez had never been out of Britain before she met her father. But earlier this year, he and his brother's family took her on a skiing holiday to Norway, where he discovered to his delight that his daughter, like him, was a daredevil on the slopes.

"When I went to Norway it was the first time I had been abroad or on a plane. We are going to Italy with him in the summer to do yoga," she says with excitement.

The Norway holiday turned into a bit of a tense affair at times, with Taylor, ever anxious to please, finding himself facing a stony wall of silence. Jez's mother says that her daughter is still coming to terms with finding out that the man she had presumed was her dad for 12 years is not, and that her real father really wants to stay around.

"On one level she is still quite wary," says her mother. "There haven't been men in her life and to present a man to her and say 'This is your dad' must be quite difficult to cope with."

Fourteen years before, Chrissy had a summer romance with Taylor, who had returned to his Glastonbury home from an American army base. "I was living in a teepee protesting about the redeployment of nuclear missiles," he explains. Fourteen years later Taylor had swapped his ponytail for a suit and tie and is now one of the Green Party's most prominent speakers. He is one of the party's best hopes to be their first MEP and needs only an 8 per cent swing to be elected next week.

But a year ago, when the existence of his long-lost daughter was first revealed to him, he almost gave up his drive to get in.

"I very nearly pulled out of the whole race altogether when I found out I was a father," he says. "It was this feeling of complete joy at discovering I had a daughter but also this feeling that her childhood was slipping away. She was 12 when I first met her. I know I didn't have much time to really get to know her. Suddenly there was this real sense of loss and trying to catch up for lost time."

Soon after he met Jez he took her shopping in Bristol to "make up for all the birthdays I had missed".

Taylor's obvious enthusiasm over his new fatherhood status is infectious: a chat about politics soon veers towards his daughter - how quick, pretty and intelligent she is and how much they have in common. "She has smelly feet just like me," he beams.

He seems desperate to become her friend and be supportive to her, but many of his efforts have up until now been greeted with a great blast of frost. "He's a lot nicer than all my mother's boyfriends" is the closest Jez gets to affection for now.

Unlike dads who've been kept awake all night by howling babies and endured the nappies and naughtiness-at-school stage, Taylor is unprepared and seems genuinely hurt by teenage "get out of my face" antics.

"We are getting there slowly. She doesn't like touching me except to kick me. But she nearly called me Daddy the other day," he says. "When she calls me Daddy that will be the moment my heart melts."